不同烟草类型间种质资源的发芽率比较

Comparison of Germination Ratio between Germplasms of Different Tobacco Types

对我国烟草中期库中保存的7个类型种质资源(烤烟、晒烟、白肋烟、香料烟、雪茄烟、黄花烟、野生种)随机抽样345份进行了发芽率测定，并采用分类方差分析法进行统计分析，同时结合发芽率跟踪检测结果研究了烟草种质保存年限与发芽率下降的关系。结果表明：①各烟草类型种质的总体平均发芽率为78．17％，烟草类型间以雪茄烟最高为87．24％；其次是烤烟，为86．24％；白肋烟最低，为76．43％。其差异达极显著水平；②制定了中期库三级更新方案，三个级别发芽率的总体频率分布以一级为主，二级次之，即目前我国烟草中期库有15％约600余份材料急需更新，30％约1000余份材料有待更新。从各烟草类型发芽率频率分布来看，白肋烟以二级分布频率最高，为42．85％；其次是三级，为34．29％；一级最低，为22．85％。其余各烟草类型发芽率频率分布与总体发芽率频率分布基本一致。在制定更新计划时，应先考虑白肋烟，其次是黄花烟；③烟草种质发芽率衰退可分为3个变化阶段。前5年发芽率衰退较快，平均每年降低1．5％，中间5年衰退趋缓，后5年发芽率衰退加速，平均每年降低2．3％。在目前保存条件下，大部分烟草种质可以维持85％以上的生活力8～10年，这取决于烟草种质最初的发芽率，同时也取决于不同烟草类型间生理指标的差异。

The germination ratio of 345 species of germplasm sampled randomly from seven types of tobacco (flue_cured, sun_cured, burley, oriental and cigar tobacco, N. rustica, and wild species) in medium-term germplasm bank were tested and analyzed statistically with classified variance analysis, and the relationship between the storage age and germination ratio was studied combining with the track testing results of germination ratio. The results were as follows: 1) the average germination ratio of the population is 78.17%, the ratios of cigar, flue_cured and (burley) tobacco are 87.24%, 86.24% and 76.43%, respectively, the difference is extremely significant; 2) a three_class (germination ratioⅠ: >80%; Ⅱ: 60%-80%; Ⅲ: <60%) refreshing project for the medium_term bank was made, the frequency distribution of germination ratio falls mainly in classⅠ, and the next in classⅡ, namely, at present, there are about 600 species of germplasm (15%) needed be refreshed immediately, and about 1000 (30%) should be refreshed; 42.85% of burley germplasms distribute in classⅡ, the other 34.29% and 22 85% in classⅢ and classⅠ, respectively; the frequency distribution of germination ratio of other tobacco types is basically the same as that of the population; therefore burley tobacco should be refreshed firstly, then N. rustica; (3) the) decline of germination ratio of tobacco germplasm could be divided into three different stages: the faster (decline) stage in the first 5 years, the average decline rate is 1.5% per year; the moderate decline stage during the following 5 years; and the accelerated decline stage, the average decline rate is 2.3% per year. Under present (storage) conditions, the viability of most germplasms would be kept over 85% for 8-10 years, depending on the (initial) germination ratio of the tobacco germplasm and the physiology index of different tobacco types as well.